Health guidelines give one clear starting number for cardio: 150 minutes a week of moderate activity. That is about 20 minutes a day, or five 30-minute sessions. It sounds like a lot until you notice what counts: a brisk walk, a bike ride to work, a swim, a game of football with friends. It does not have to be a "workout", and it does not have to happen in one go.
If you are brand new, treat 150 as a destination, not an entry fee. Public health guidance is also clear that some activity is better than none, so ten minutes today beats zero minutes while you wait for the perfect plan.
The guidelines split effort into two levels. You do not need a watch to tell them apart, because the talk test works well:
Harder minutes count for more. The guideline lets you swap 75 vigorous minutes for 150 moderate ones, so a vigorous minute is worth about two moderate minutes. That is a rule of thumb, not a law of physics, but it is a handy way to add up a mixed week.
Below is a blank week. Set the minutes for each day and tap the intensity button. The bar shows your total in "moderate minutes", where vigorous minutes count double.
Going from nothing to 150 minutes in one week is a jump, and sore shins or burnout are common results. A gentler way is to begin with what you can repeat easily, such as three 10-minute walks, and add a few minutes every week or two. Slow and steady keeps you coming back, and coming back is the whole game.
Spread the minutes however suits your life. Five 30-minute sessions, three longer ones, or lots of short bursts all count toward the total. Choose activities you do not dread, because the plan you stick to beats the optimal plan you quit.
150 minutes is a baseline, not a ceiling. Guidance says doing more brings extra health benefits, but there is no hurry to get there. Cardio is also only half of the picture: adults are advised to do muscle-strengthening activity on at least 2 days a week, which is what the strength guides on this site are for. Walking and lifting fit together well.
The numbers above are for generally healthy adults. If you are pregnant, have a heart or lung condition, have had chest pain or dizziness with effort, have joint pain, or are recovering from an injury, check with your doctor or a physiotherapist before you raise your effort or minutes. Stop and get advice if exercise causes chest pain, unusual breathlessness or faintness.